1. Field of the Invention
The present invention relates to a method for controlling a resolution of a graphic image and more particularly to a method for controlling a resolution of a graphic image when various electronic devices such as a personal computer (PC), a set-top box (STB) equipped with an Internet function, etc. enable an external display unit such as a television (TV) or etc. to display the graphic image.
2. Description of the Related Art
Recently, there is increasing the case where an external display unit such as a television (TV) is used while being coupled to a personal computer (PC) or a set-top box (STB) equipped with an Internet function. As shown in FIG. 1, a personal computer (PC) 100 includes a central processing unit (CPU) 10, a graphic card 11, a keyboard controller 12, a disc drive 13 and an Internet module 14. Here, the PC 100 can be used while being coupled to a monitor 200 or television (TV) 300.  Where a user makes a request to change the resolution of a graphic image displayed on the monitor 200 using a keyboard or mouse, the CPU 10 sets a “display control mode” through an interface with the keyboard controller 12 coupled to a bus line. The CPU 10 confirms the graphic image's resolution value selected by a user from among the conventional monitor's resolution values, e.g., “640×480” pixels, “800×600” pixels, “1024×768” pixels, “1152×864” pixels, “1280×1024” pixels, “1600×1200” pixels, etc.  Furthermore, the CPU 10 controls the graphic card 11 so that the graphic image's resolution value selected by the user is set and stored. The graphic card 11 refers to the set resolution value of the graphic image and controls the number of horizontal and vertical pixels of the graphic image to be displayed on the monitor 200. Thus, the monitor 200 displays a graphic image of the number of pixels corresponding to the set resolution value. As shown in FIG. 2, a top portion of the monitor screen fully displays a menu bar.  On the other hand, where the PC 100 is used while being coupled to the TV 300, the CPU 10 sets a “display control mode” in response to a user request. The CPU 10 confirms the graphic image's resolution value selected by the user from among the resolution values capable of being accommodated in the conventional TV, e.g., “720×480” pixels, “1920×1080” pixels, “1280×720” pixels, etc.
Furthermore, the CPU 10 controls the graphic card 11 so that the graphic image's resolution value selected by the user is set and stored. The graphic card 11 refers to the set resolution value of the graphic image and controls the number of horizontal and vertical pixels of the graphic image to be displayed on the TV 300. Thus, the TV 300 displays a graphic image of the number of pixels corresponding to the set resolution value as shown in FIG. 3.
However, where the PC is used while being coupled to the conventional TV in which a size of a valid screen displaying the conventional video image is smaller than that of an actual physical screen, part of an outer portion of the graphic image is not appropriately displayed as shown in FIG. 3. In particular, where the menu bar to be selected by the user is located at the top portion of the graphic image, there is a problem in that a menu item desired by the user cannot be selected because the menu bar cannot be displayed on the valid screen.
Furthermore, where the graphic image is displayed after the resolution of an externally received graphic image is controlled using a scaling technique in the conventional TV, there is another problem in that characters contained in the graphic image are distorted and the distorted characters are displayed.